1. Field of the Invention
The present invention relates to a heat dissipation apparatus, and in particular to a heat dissipation apparatus having an unpowered fan.
2. Description of the Related Art
Generally speaking, conventional heat dissipation technique for a computer focuses on life span extension of computer components and enhancing efficiency of the heat dissipation device in the computer. The lifespan extension of the heat dissipation device is usually ignored. When the conventional heat dissipation device malfunctions, heat generated by the computer components cannot be dissipated and creates a high temperature on the computer components. Thus, the computer components are easily damaged due to the high temperature, even though the lifespan of the computer component may be far from over.
The conventional heat dissipation device requires electric power to be actuated. For the heat dissipation efficiency to be enhanced, the rotation of the motor is increased. When the motor rotates at a high speed over a long period of time, the lifespan of the motor is reduced due to friction or wear among the body and inner elements thereof. In addition, the heat generated by the computer components increases tremendously when the rotation of the motor increases. Thus, heat dissipation efficiency is reduced. Even though the computer components may continuously function, computer damage resulting from insufficient heat dissipation may be caused and the lifespan of the computer is thus reduced. Accordingly, cooling is critical in maximizing the lifespan of the computer system.
FIG. 1 is a perspective assembly view showing a conventional cooling fan 5 for a CPU 3 and FIG. 2 is a perspective exploded view according to FIG. 1. The fan 5 is disposed on the CPU 3 and a heat sink 4 by engaging portions 51 and engaging elements 21. The fan 5 provides airflow to the heat sink 4 to dissipate the heat generated by the CPU 3. Nevertheless, in the computer system, heat is continuously produced and cannot be dissipated efficiently, such that the temperature of the computer system increases quickly. According to the theory of temperature gradient of thermal dynamics, heat dissipation efficiency is reduced because the temperature gradient in the computer system is increasingly reduced as the computer system is working for a period of time. Even if the rotation of the fan 5 is increased or the structure of the fins 44 of the heat sink 4 is improved, the temperature gradient is not increased. As well, the increased rotation of the fan 5 reduces lifespan thereof. Finally, the failure of the fan 5 can cause computer system damage.
Consequently, the invention provides a heat dissipation apparatus to overcome the aforementioned problems. The heat dissipation apparatus includes an unpowered fan to dissipate the heat generated by the computer components. Since the unpowered fan is not driven by a motor, the lifespan of the unpowered fan is prolonged tremendously. Specifically, the unpowered fan is driven by thermal convection between a heat source having a high temperature and an outlet having a low temperature. Thus, air in the computer system is intensely stirred. The heat or hot air does not accumulate on the heat source and is guided out via the outlet rapidly and evenly by the unpowered fan. Additionally, the heat dissipation apparatus includes a temperature gradient maintaining device disposed on the outlet of the computer system. The temperature gradient is not increasingly reduced as the computer system works for a long period, thus enhancing the heat dissipation efficiency thereof.
An object of the invention is to provide a heat dissipation apparatus for a computer system. The computer system has a heat source. The heat dissipation apparatus comprises an outlet, a temperature gradient maintaining device and an unpowered fan. The outlet is disposed on one side of the computer system. A thermal convection route exists between the heat source and the outlet. The temperature gradient maintaining device provides and maintains a temperature difference between the heat source and the outlet. The unpowered fan has a plurality of blades and is disposed on the thermal convection route.
Preferably, the unpowered fan is disposed beside the heat source.
Preferably, the temperature gradient maintaining device is disposed on the outlet.
Preferably, the temperature gradient maintaining device maintains the temperature difference between the heat source and the outlet at 30xc2x0 C.xcx9c50xc2x0 C. to keep the unpowered fan rotating continuously.
Preferably, the blades of the unpowered fan are plastic.
Preferably, the temperature gradient maintaining device is a cooling device.